Spark-plug tester



June 24, 1930. H" *SW-ARTI SPARK PLUG TESTER Filed May 22, 1928 2 Sheeisheetl swag. l :ma:

Patented June 24, 1930 appncaibn mea'nay '22, 16526.y serial No. 279,666.Y

' Mzyl invention relates torviinprovementsl'fin devices tor testing spark fplugs 'to determine whether or not said spark plugs are kcapable of producing aneilicent spark' under operaty ing conditions and thegobject .ofmy invention is toprovidea A'device in which a spark plug may be tested andthe results of the tests ob- Y served while the terminals of the said spark plug are surrounded by air under a relatively high pressure, whichpressure may be approximately the same as the pressure lunder which the spark plug'is required to operate when it is in kan an internal combustion enine.y Y

Another object is to provide a spark'plug tester embodying'a housing formed` inpart of transparent material and in part' of metal, said metal part having openings for receiving and holding spark plugs so that the terminals of said plugs lare within said housing and may be seen through the transparent portion of the same, said vhousing having a pressure gauge thereon and being connected with means for admitting air .under pressure and said testing device being provided with meansV for supplying electric current to the spark Plugs. l

Other and more specific objects will be apparent from the following description takenY in connection withA the laccompanying drawings. i K Inthe drawings Figure 1 is a plan View of a spark plug tester constructed in accordance with'my invention. t l l i Fig. 2V isa cross section of the same sub stantially on broken liney 24,2 of Fig. 1.

Fig. 3 is a side elevationvof one side of the f n device.V t Y f A Fig. 4 is a sectional view onbroken'line '44-40fFig3.

Referring tothe drawings, throughout which like reference numerals designate like parts, 5 and 6 designate two upright spaced Parallel end plates betweenfwhich is disheavy Glass.- Thefend plates 5 and 6 are Vcounterim l Vfor the reception of the. ends of the cylinder 7' and sealing washers-orgaskets 9 of soft air tight material are interposed between the posed a hollow cylinderv'of relatively strong as at 8l on their inner surfaces end plates and the endsoi the cylinder l7. Bolts or yscrews 10 extend crosswise between the end: plates 5 and 6 at suitable-intervals around the cylinder. 7 for clamping the: end

'pf-lates tightlyagainst-the.ends off the Acyline 55 v der.: 'lhetwo end plates 5` and 6,;liayesiiitable bossesy wherein .are provided,A internally threaded openings 111-,.12 13,gsee Fig.lAf,'

for .the reception of sparkfZ-plugs 14, l'j'and' I vv16 respectively. In practice 'I lindthat three 60 of. said openings of diii'erent-.siz'e are vall that are :needed for the` various sizes of Vspark plugs now. .on .the market, but.l it is obvious that as many 'of said'y openings ofjdierenty size asyare. desired maybeprovided.

fOne of .the Vend` plates ,5i is provided with a boss 18 having an opening 19 formed there-Vv infor the inlet of air yunder pressure:` Said opening 19 .is '.connectedrthrough a nipple '2O and three-way valve 21wth an air supply 70 conduit, as alhose'22. y I' Y v A' .pr essuregauge.23 is connected with the interior of ythe, housing-.7 by. aniopening 24 formed in a boss 25 on the vend. plate 5. j

The electrical `,connections -to lthe .spark ,75 plugs embodytwic'rv flatY springs .26f .and 27 v of` one or more plies .of thinresilient electrif cally 'conductive r inet-al. Q'lhese y,springs .are mechanically/ and electrically connected byy y screws 28to the endsjotametalrod,295*biit .80l

are', free to be turned by vhand as here'inafter explained.y The. metal rod zS29 isk enclosed within a tube 30,01: insulating-materialand the tube'30 is disposed within an outermetal- 'end platesand 6. Y Y v Y A circuit wire33 is connected by a clip 34 v withv the metal rod y28. Suitable'hinsulation washers 35 are provided -:tor insulatingthe springs 26 and 27 and the clip 34 from the tube 90, 31. The circuit wire 33fisfconnectedthrough tubelwhich vis supported in lugs T32 on the p85 .binding/post 37 withfa rsuitable'y transformer v notishoWm-which'is contained within'the box f 36L The transformer may 'jbeof' anyfstand-k ardtype commonly used in'automobile igni- 95; Y

tion systems. A manually c operatedv switch y 38 maybe Aprovidedfon the top ofthe coil box 36 'to 'open 'and close the v"circuit-tothe sparkl n Y plugs, onefterminal of leach spark plug being 10o 1' groundedon end plates 5 and 6;

I pensive to manufacture and gives aVV reliablervf" 'l o .A

sired amount ofcompressed airpmay bef-adf v TheY end plates fandk 6 preferably Yrest upon kand are secured to the top Vof the box ,36 thus making a veryV convenient'and unitary construction Binding posts 89 may be Vproi 5 vided on the front end of the box 36 as shown.

' [The binding post37 ,Y switch 38and binding y posts39., are essentially insulated from box 36./

l Y Suitable plugs,V notY shownflmay be provided torv closing thei'openings12, .13 r`and 14 19 Y when no spark? plugs arel contained therein.;

In the operation 'of thisA spark plugYY tester the-plug V or plugs tol be tested fare screwed'- tightly into theopenings 11,' 12 andV 13 'and thevcontact springs 26 and12y7; turned so'v asto,y

i5v engage the ends of said sparkVY plugs; air is thenj admitted "to raise Y the pressure aroundtheterminals -39 ofjsaid spark plugs to Vap-` proximately thelknown pressure under Ywhich the'v plu-gis' are Vrequired to 'lire Vin" an internal v Y 2U combustin-engine as indicatedby the presi sure gauge; electric current is then-admitted l to theplug by closing switch S'Szand the nar` V end of said rod, and means for supplying Y f electric current to said rod.

2. Aspark plug tester,'embodying ahollo-w 1 l glass cylinder, two end platesfformlng air tight closures for the ends of saidcyli'n.ders',V 76

saidl end plates YShaving threadedopenings ,into -which sparklplugstmay.. be screwed; Q f '7" means for supplying air under pressureto said e cylinder; ametal rod extending crosswise of said end plates and?insulated'therefrom, a `75 ,i l" Ycontact spring pivotally connected with each Y. rend of said rod and arranged to beplaced 1n Y contact 'with the outer ends of the sparkplugs,

the, innerendsofgthe spark plugs beingy i i grounded on Said end plates,V aY coil box sup- 85; porting said endl platesgandmeans` for lsup- 5 Y plying current from the coil box to said metal i Tod. v.. .,1 Y In Vwitness whereoL-I hereunto subscribe my. mmeV thisiith day fMay, A. '13.1928. jg;

Huren-Swann V'lureof"thesparkthereby producedY 'is obi served.l In testing'the spark plug the vair pres- 25 sure may be gradually raised withinthe hous-V fing'7and'1the1switch` SSpened Vand closed repeatedlyr untilapressure' isreached'atwhich I i lthe spark plugceases to'fun'ction and no1 spark` Y l d `isVproduced. This shows the pressure" at *p p30 which any particular spark plug willlbreak down.` `The lelectrical connectionsto the spark 5 and 6. x

d V f plugs Vare 'completed'by groun'dingr'on platesv y workingk partstoget out of orderyis not ex# and efficient test oftheplugs under substantially the Y workingjfconditons fot said e plugs f The valve 21 is arranged. so "that the demitted to the receptacle andthe valvelthen turned so as Vtocloseoilg the sourcerofsupply *Y YAYand hold said pressureJ/in said jreceptacle, v f whichipressu're maybe-loweredby turning Y l H aid-valve toathirdrpositiontoexhaust'some f f Qi allof thejair from the receptacle," 1 f I f' fI-he'lforegoing description andaccompany-i t f ing drawings clearly disclose a preferredv em-V bodiment of my inventionlbut itfwill beuunv 7,1 Yderstood that this disclosure 'is'.,merely illus#Y` 4'The devi'celis simplein construction, has no Y ltrati'vefand .thatsuchrchangesrmay'be made as are fairly" within the scope and spirit Vfol? Y the following claims ings into'which'sparkV plugs may 4be jsc'rewedg I kymeans;for'supplying air underpressure toi. Y

Isaidcylinder, a'metal-ro'd extending crosswi'se Y p J of saidendplates and'insulated therefronna e5 contact spring vpivotally connected'with the'` Y gicav nuv Y Yiro. 

